Well, it takes 2 users to make 1 friendship, so it would be half of that. Plus that's the number of daily users, the total number of users is like double. So the average friends per user must be around 65.

The average is 190.

http://arxiv.org/pdf/1111.4503v1.pdf

Huh?

There's 125 billion friendships and 900 million monthly active.

125 billion / 900 million = 139 friendship pairs / user

A pair = 2 friends so you double it to get 278 friends/users.

This is of course an overestimate as people are friends with people who use fb < once a month. Not sure what total user count is though.